Brush spring retractor



May 16, 1950 H, KRAUSE 2,507,981

BRUSH SPRING RETRACTOR Filed March 30, 1949 Zmventor Gttornegd PatentedMay 16, 1950 BRUSH SPRING RETRACTOR Herbert A. Krause, Brookfield, Ill.,assignor to General Motors Corporation, Detroit, Mich, a

corporation of Delaware Application March 30, 1949, Serial No. 84,427

4 Claims.

The present invention relates to retracting tools and more particularlyto a retracting tool for the brush fingers of dynamoelectric machines.The principal object of the invention is to provide a compact retractingtool which is readily engageable with the various brush fingers of thebrush holders located in the confined space adjacent the commutator orslip rings in dynamoelectric machines for readily retracting thesefingers.

Another object is to provide releasable tool latching means engageablewith a portion of the brush holder to retain the tool and brush fingerengageable thereby in the retracted position in order to readily andsafely replace the brushes.

The novel features of the tool by which these objects are accomplishedare clearly described in the following detailed description and areillustrated in the accompanying drawings.

Figure 1 of the drawings is a side elevational view of the retractingtool shown engaged with a brush finger in the normal operative position.

Figure 2 is a view similar to Figure 1 with the tool and brush finger inthe retracted position and retained in this position upon engagement ofthe latching means of the tool with the brush holder.

Figure 3 is an enlarged perspective view of the tool showing thespecific details of the tool assembly.

As best shown in Figure 3 the brush retracting tool comprises a mainlever I having a handle portion 3 at the outer end and a bifurcatedinner end fulcrum portion. The two legs 5-| of the bifurcated fulcrumportion are downwardly curved at the extremities thereof. Brush fingerengaging means are provided on the lever I comprising a dependingU-shaped stirrup 9 secured to the lever intermediate the ends. The leveris shown provided with an upstanding side portion intermediate the endsand a latching lever I3 is pivoted intermediate its ends by means of apivot pin 5 to this upstanding portion l of the main lever for angularmovement relative thereto. The latching lever I3 is provided with anouter end handle portion I located above the handle portion 3 of themain lever and a downwardly extending hooked portion I9 is provided onthe inner end of the latching lever located above the leg 5 of thebifurcated inner end fulcrum portion of the main lever I. A leaf spring2| is secured at one end to the upper face and at one side of the mainlever handle portion 3 and the other end of the spring 2| extendsupwardly and engages the underside of the latching lever handle portionI 1 adjacent the pivot pin 5 to oppose angular movement of the latchinglever handle portion angularly into engagement with the main leverhandle portion 3 and normally retain the portion of the latching leveradjacent the hooked inner end portion 19 in contact with the leg 5 ofthe main lever fulcrum portion.

The above described brush finger retracting tool is shown in Figure lwith the depending stirrup 9 of the main lever engaged with a hookedportion 23 of a brush finger I25 and the curved legs 5-'| of thebifurcated fulcrum positioned along opposite sides of a spring anchorlever 21 of a brush holder frame 29 of well known type secured inconventional manner to the stator of a dynamoelectric machine, notshown, adjacent the peripheral surface 3| of the commutator or sliprings, shown in dotted line, of the rotor of the machine. The springanchor lever 21 is provided with a hub portion 33 pivoted on aninsulating bushing 34 on a pin 35 supported at the ends on the brushholder frame 29. The anchor lever may be positioned angularly withrespect to the bushing and held in different angular positions thereonby means of a key 36 engageable in one of a plurality of slots 31 in thehub portion 33 of the anchor lever. The key 36 is releasably secured bya machine screw 38 to the brush holder frame 29. The brush finger 25 isalso pivoted on the bushing 34 by means of side bearing portions 39spaced axially either side of the anchor lever hub portion. A brushfinger spring, generally indicated at 4| having the opposite ends 43shown hooked over the finger side bearin portions 39, adjacent helicalportions 45 around the portions of the bushing 34 and an upstandingcentral loop portion 41 engageable with the opposite ends of a pin 49secured in an opening in the end of the anchor lever 21 serves to urgethe outer end of the finger 25 into contact with the outer end of abrush 5| slidable in a slot 53 in the brush holder frame and therebyhold the inner end of the brush in firm contact with the peripheralsurface 3| of the commutator or slip ring.

The main lever l of the brush finger retracting tool is shown in Figurel in position to retract the brush finger 25. The curved legs 5-! of thebifurcated fulcrum portion of the main lever are shown engaged with thehelical portions 45 of the spring and the main lever stirrup 9 is inengagement with a hooked portion 23 of the brush finger. It will beevident that clockwise movement of the main lever I from this engagedposition moves the brush finger 25 clockwise away from the brush 5|against the action of the finger spring 4| and the hooked end IQ of thepivoted latching lever is positioned by the leaf spring 2! to engage thekey 36 and hook over the outer end surface thereof, as shown in Figure2, when the brush finger is fully retracted to hold the tool and fingerin .the'retracted position. The leaf spring 21 serves in the same mannerwhen the retracting tool is inverted and engaged with the brush fingerin another brush holder frame positioned adjacent the diametricallyopposite or lower side of the commutator 'or slip ring surface 3|.

The construction of the above described retracting tool enables brushfingers located in the limited space available in dynamoelectricmachines to be easily retracted and held -in this position whereby thebrushes may be :safely replaced.

.I claim:

. 1. Jin zaretracting tool .for-a spring biased brush finger pivoted in:a brush holder 'of Ta dynamo- .electric machine, a main lever, alatching lever pivoted thereon, xsaid main lever having brush fingerengaging .means and a fulcrum portion .engageable with .a portion of thebrush holder, said latching lever having a hooked end portion engageable.with another portion of the brush holder when "the finger is retractedby the main lever.

2. In .a retracting tool :for' aspring biased brush ifinger pivoted in a:brush holder of a "dynamofe'lectric machine, a main lever having brushfinger engaging means and a fulcrum portion "contactable and movablewith respect to the brush =holder, a latching lever pivoted on the 4main lever and having a latch portion engageable with another portion ofthe brush holder when the main lever is moved relative to the brushholder to retract the brush finger and a spring normally urging thelatching lever.

3. In a retracting tool for a spring biased brush finger pivoted in adynamoelectric machine brush holder, a main lever having a handleportion on the outer end, a fulcrum portion on the inner end adapted toengage a portion of the brush :holder and means intermediate the endsengageable with the brush finger, a latching lever pivoted intermediatethe ends on the main lever,

a hook-shaped inner end portion adapted to releasably engage a portionof the brush holder when the finger is retracted, and a springenvgageable with .the handle portions of both levers normallypositioning the hook-shaped inner end portion of the latching lever forengagement with the brush holder.

.4. In a retracting .tool for a spring biased brush fingerinadynamoelectric machine brush holder,

a main lever having brush finger engaging means intermediate the ends, abifurcated fulcrum inner end portion engageable with the brush holdereither side of the fingerand an outer end handle portion, a latchinlever pivoted intermediate the ends to the main lever, a hook-shapedinner .end portion and an outer end handle portion and spring means forurging the handle portions of the mainand latching levers apart andpositioning the .hookeshaped inner end ,portion of .the latching lever.into releasable latching engagement with the brush holder uponretraction of .the finger when engaged by the main lever.

HERBERT A. .KRAUSE.

No references cited.

